There are a number of assembly operations in which two lengths of pipe must be joined with the end portion of one telescoped inside the end portion of another, and this is most easily done by the use of a U-bolt and cooperating arcuate saddle which is most commonly secured to the U-bolt by threading the legs of the U-bolt and using nuts to clamp the U-bolt and the saddle from around the pipe.
Probably the largest volume usage of such connections is in the automotive industry, where a muffler has one end connected to a pipe from the exhaust manifold or the catalytic converter, and has the tail pipe connected to its other end.
The difficulty with the conventional threaded U-bolt and nut arrangement is that it is relatively slow to apply even if a pneumatic torque wrench is used to tighten the nuts. Labor is a large item, and it is about the same whether the muffler and tail pipe are being mounted on a new automobile at the factory or are replacement parts being mounted in a service shop.
There have been a number of efforts to provide a U-bolt clamping structure which can be applied by the use of a compact hydraulic, pneumatic, or manual press; and the most pertinent of these known to applicant or his attorney is disclosed in Oldford U.S. Pat. No. 4,015,313, issued Apr. 5, 1977. Also pertinent is Johnson U.S. Pat. No. 2,741,938, issued Apr. 17, 1956, which discloses a threadless bolt and resilient retainer which could be adapted to a U-bolt and saddle construction.
In addition to the reduced labor costs which may be achieved by eliminating a threaded U-bolt and nuts, the mechanical components themselves may be considerably less expensive if precision threading of U-bolt and nuts can be avoided, and the long U-bolt shanks usually required can be reduced in length with a resultant material saving.